The present invention relates to a fixing apparatus for use in, for example, electrophotographic copier, which is designed to fixing an image transferred on a paper sheet, and also to a fixing method and an image forming apparatus.
An electrophotographic copier forms a toner image on the photosensitive drum and transfers the toner image to a paper sheet. The paper sheet with the toner image transferred to it is supplied to the fixing apparatus. The fixing apparatus fixes the toner image on the paper sheet.
The fixing apparatus comprises a heat roller and a press set in press contact with the heat roller. As the paper sheet having a toner image transferred to it passes through the contact portion between the heat roller and the press roller, it is heated and pressed. The toner image is thereby fixed.
At the time of fixing the toner image, dirt such as toner may stick to the surface of the press roller. A cleaning roller made of metal is pressed onto the press roller, thereby to remove the dirt from the press roller.
To enhance the efficiency of transporting the paper sheet, the press roller of the fixing apparatus is shaped like a so-called "reversed crown," having its diameter gradually decreasing toward the middle portion from either end.
Hitherto, the cleaning roller, which is shaped straight, is pressed onto the press roller that is shaped like an reversed crown. The cleaning roller fails to contact the press roller at its middle portion, though it well contacts the press roller at its end portions.
It is therefore impossible to removed the dirt from the middle portion of the press roller. Consequently, the paper sheet may gets dirty in the process of fixing the image.